ZOJ 3469 区间DP Food Delivery

题解

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <map>
 #define MP make_pair
 using namespace std;

 typedef pair<int, int> PII;

 const int maxn =  + ;
 const int INF = 0x3f3f3f3f;

 PII a[maxn];
 int sum[maxn];

 int n, v, x;

 int d[maxn][maxn][];

 int main()
 {
     while(scanf("%d%d%d", &n, &v, &x) == )
     {
         for(int i = ; i <= n; i++) scanf("%d%d", &a[i].first, &a[i].second);
         a[++n] = MP(x, );
         sort(a + , a +  + n);
         for(int i = ; i <= n; i++) sum[i] = sum[i - ] + a[i].second;

         int p;
         for(int i = ; i <= n; i++) if(a[i].first == x) { p = i; break; }
         memset(d, 0x3f, sizeof(d));
         d[p][p][] = d[p][p][] = ;

         for(int i = p; i > ; i--)
             for(int j = p; j <= n; j++)
             {
                 if(i == j) continue;
                 int t = sum[i - ] + sum[n] - sum[j];

                 int& ans1 = d[i][j][];
                 ans1 = min(ans1, d[i+][j][] + (t + a[i].second) * (a[i+].first - a[i].first));
                 ans1 = min(ans1, d[i+][j][] + (t + a[i].second) * (a[j].first - a[i].first));

                 int& ans2 = d[i][j][];
                 ans2 = min(ans2, d[i][j-][] + (t + a[j].second) * (a[j].first - a[i].first));
                 ans2 = min(ans2, d[i][j-][] + (t + a[j].second) * (a[j].first - a[j-].first));
             }

         printf("%d\n", min(d[][n][], d[][n][]) * v);
     }

     return ;
 }

代码君